1. Field of the Invention
The present invention relates to an optical fiber switching device, and more particularly to an optical fiber switching device that relies upon linear motion to change switching positions, and precisely align light output side with light input side so as to enhance the accuracy of the optical fiber checking.
2. Description of Related Art
Optical fibers are widely and popularly applied to be a medium of data transmission, because the data transmission speed of the optical fiber is extremely fast, moreover the bandwidth of the optical fibers is much broader than conventional cables and telephone lines. Thus, the optical fibers are often applied to transmit a great quantity of data, such as video signals and voice signals, to immediately transmit data. When an optical fiber network has been set up, an important procedure is to check whether the optical fiber has been damaged.
For the purpose of checking the optical fiber, an optical switch is disclosed in U.S Pat. No. 4,378,144 (""144) by Duck, et al.
With reference to FIG. 8, the optical switch in the ""144 patent comprises a motor (60) having a threaded axial extension (70) attached to its shaft (61) with a nut (75) received upon the threaded axial extension (70). The nut (75) has a short lower arm and a long upper arm (74). A guide spindle (71) supported at two ends thereof by a first pillar (72) and a second pillar (73) extends through the lower arm of the nut (75). The guide spindle (71) is held parallel to the extension (70), and a distal end of the extension (70) is supported by a bearing block formed on top of the first pillar (72).
On a light input side of the optical switch there is provided a first collimating lens (80) attached to one end of an optical fiber (82), the first collimating lens (80) being secured in the upper arm (74) of the nut (75).
On a light output side, the optical switch comprises a group of second collimating lenses (81) attached to the ends of optical fibers (not shown), one second collimating lens (81) to each optical fiber. As shown, the second collimating lenses (81) are disposed in a side-by-side straight line relationship.
In accordance with the foregoing description, when the motor (60) drives the threaded axial extension (70) to rotate, the upper arm (74) is linearly moved along the threaded axial extension (70) so that the first collimating lens (80) is sequentially moved to align with the second collimating lenses (81). However, only one fulcrum is defined between the upper arm (74) and the guide spindle (71), thus the upper arm (74) easily inclines out of alignment (as shown in FIG. 9) and the first collimating lens (80) is consequently mis-aligned with the second collimating lenses (81). Due to the mis-alignment of first collimating lens (80) and the second collimating lenses (81), the light signal transmission has a significant loss, and thus a serious error occurs in the optical fiber inspection procedure.
The optical switch has a further disadvantage which is: The upper arm (74) is only supported by the guide spindle (71) and thus easily inclines, hence assembly of the optical switch requires special care to ensure that the optical switch will operate precisely.
To overcome the shortcomings, the present invention provides an optical fiber switching device to mitigate and obviate the aforementioned problems.
The main objective of the invention is to provide an optical fiber switching device to precisely align a light input side with a light output side so as to increase the accuracy of an optical fiber inspection process.
The second objective of the invention tends to provide an optical fiber switching device having a small quantity of components so as to enable easy assembly of the optical fiber switching device.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.